1. Field of the Invention
The present invention relates generally to a ball valve, and more particularly to a ball valve comprising a fireproof structure to minimize leak of the ball valve in case of fire.
2. Description of Related Art
As shown in FIGS. 1, 1A, 2, and 2A, the prior art ball valves comprise a valve body 10, a spherical body 12, and two leakproof rings 13. The spherical body 12 is provided with a channel 11. The leakproof rings 13 are susceptible to wear or deformation due to the mechanical friction between the leakproof rings 13 and the spherical body 12. In light of the damage or deformation of the leakproof rings 13, leak takes place between the spherical body 12 and the leakproof rings 13.
As shown in FIGS. 3 and 3A, another prior art ball valve comprises a valve body 20, a spherical body 21, two leakproof rings 22, and an urging member 23. As shown in FIG. 3A, the urging member 23 is formed of a movable block 24, an elastic element 25, and a locating member 26. The movable block 24 is provided in two sides thereof with a slot 27 for locating one of the leakproof rings 22. The movable block 24 is urged by the elastic element 25 so as to keep the spherical body 21 and the leakproof rings 22 in contact with each other. The leakproof rings 22 are made of Teflon and are vulnerable to deformation or meltage in the event of fire. The molten Teflon rings 22 are either attached to the spherical body 21 or carried away by the fluid flow, thereby resulting in the valve leak.
The primary objective of the present invention is to provide a ball valve with a fireproof structure to overcome the deficiencies of the prior art ball valves described above.
The foregoing objective of the present invention is attained by the ball value comprising a valve body, a spherical valve block, two leakproof rings, and an urging member for keeping the spherical valve block in an intimate contact with the leakproof rings. The urging member is formed of a movable block, an elastic element, and a locating element. The movable black is provided with two slots for locating the leakproof rings, and two annular protruded edges located respectively in proximity of the leakproof rings. In the event of deformation of the leakproof rings, the reaction force of the elastic element pushes the leakproof rings to make contact with the valve block. In the event that the leakproof rings are melted, the valve block is pressed by the annular protruded edges, so as to minimize the valve leak.
The foregoing objective, features and functions of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings.